1. Field of the Invention
The present invention relates to a scroll type compressor which is a coolant compressor used in a freezer or air conditioner and is provided with a coil-like fixed scroll and an oscillating scroll that interlocks with the fixed scroll to form a compression space in which the volumetric capacity of the compression space is varied with the oscillating motion of the oscillating scroll to compress the coolant.
2. Description of the Related Art
A scroll type compressor of the prior art is provided with a drive shaft that is rotated by a means for driving such as an electric motor, an oscillating scroll member which is mounted eccentrically on the drive shaft and a fixed scroll member that interlocks with the oscillating scroll member to form a compression space (scroll chamber). The volumetric capacity of the scroll chamber is varied by oscillating the oscillating scroll member relative to the fixed scroll member to take in, compress and discharge the coolant. Thus, the lubrication and sealing of the various sliding contact surfaces of the scroll type compressor are crucial factors.
Accordingly, the scroll type compressor disclosed in Japanese Patent Unexamined Publication No. H3-149391 includes a rotary displacement type oil pump in its structure, so that a sufficient quantity of lubricating oil can be reliably supplied to the bearings regardless of the flow rate of the lubricating oil supplied to the compression work space. With this, a large quantity of lubricating oil can be assured against high loads applied to the sliding contact surface of the oscillating scroll member, the drive shaft and the main bearing provided in the area where the drive shaft slides against the block that secures the fixed scroll member, the thrust bearing provided in the area where the scroll member slides against the block and the like.
Also, the scroll type compressor disclosed in Japanese Patent Unexamined Publication No. H3-61689 is provided with a cylinder section in the direction of the reciprocal movement of the oldham's coupling, which prevents auto rotation of the oscillating scroll member, on the wall surface facing opposite the external circumferential surface of the oldham's coupling. A liner is provided that moves back and forth within the cylinder in conformance with the operation of the oldham's coupling to push out the lubricating oil. This structure allows the quantity of supplied oil to be increased as the number of rotations of the drive unit increases.
Likewise, Japanese Patent Unexamined Publication No. H3-105093 discloses a scroll-type compressor in which a pressurized passage, which is subject to centrifugal force from the drive shaft, is formed in the drive shaft running towards the outside in the direction of the radius of the drive shaft, constituting a so-called centrifugal pump to supply lubricating oil.
However, with the scroll type compressors in the examples cited above, if a non-ferrite material, such as an aluminum alloy is used for the fixed scroll member and the oscillating scroll member in order to reduce weight and cost, the following problem arises since the back pressure applied to the oscillating scroll member is high, the force that is applied to the oscillating scroll member toward the fixed scroll member results in seizure of the sliding area where the oscillating scroll member and fixed scroll member are in contact with each other.